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Proper Use of the KX Modifier for Part B Immunosuppressive Drug Claims

A 2017 Office of the Inspector General (OIG) report noted that, in some cases, pharmacies incorrectly billed Medicare Part B for claims using the KX modifier for immunosuppressive drugs. It is estimated that Medicare paid $4.6 million for these claims that did not comply with Medicare requirements.

In response to this report, CMS clarified manual instructions on the use of the KX modifier to help pharmacies document the medical necessity of organ transplant and eligibility for Medicare coverage. Resources for pharmacies: